1. Field of the Invention
This invention relates to inner quaternary ammonium salts of copolymers. More especially, this invention relates to the reaction product of a polymer having an amine group, especially a tertiary amine group, and an .alpha.-.beta.-unsaturated C.sub.3 --C.sub.6 aliphatic carboxylic acid. More especially, this invention relates to the use of such a polymeric material as a detergent for fuels, especially gasoline. This invention is particularly concerned with inner quaternary ammonium salts of copolymers having an amine group and their use to remove deposits from an engine carburetor.
2. Discussion Of The Prior Art
Various detergents have been proposed for use in fuels, especially gasoline. For instance, it has heretofore been proposed to employ as a gasoline detergent a condensation product of a secondary C.sub.10 amine with maleic anhydride. Similarly, it has been proposed to use an amine of polyisocyanate detergent. Both of these known types of gasoline detergents are effective in removing deposit build-up from an automotive engine carburetor. However, the known commercially available types of gasoline detergents are particularly costly in production, thus adding to the final cost of gasoline at the pump.
It has become desirable, therefore, to provide less expensive, yet effective, gasoline detergents. It has heretofore been proposed by Catlin et al in U.S. Pat. No. 2,737,452 to employ as a fuel oil stabilizer at least 0.001 percent by weight of an oil soluble basic amino nitrogen-containing addition type polymer of a plurality of polymerizable ethylinically unsaturated compounds, at least one of which is amine-free and contains about 18 carbon atoms in an aliphatic hydrocarbon chain which, while in the polymer, is not part of the main polymer chain. The polymer also contains units which supply a basic amino nitrogen in a side chain, the polymer containing 0.1 to 3.5 percent by weight of basic amino nitrogen. The basic amino nitrogen is supplied by a compound such as .beta.-diethylaminoethyl methacrylate. Such stabilizers are effective in stabilizing catalytically cracked fuel oils. They possess some degree of detergency.
It has become desirable to provide more effective and different gasoline detergents. More especially, it has become desirable to provide more effective detergents which are polymeric in nature and are derived from both nitrogen-containing and nitrogen-free comonomers.